Method of preserving timber.



UNITED STATES PATENT OFFICE.

' WILLIAM onoss, or BRISBANE, QUEENSLAND.

METHOD OF PRESERVING TIMBER.

SPECIFICATION forming part of Letters Patent No. 643,762, dated February 20, 1900.

Application filed September 1; 1899. Serial No- 729,249. (No specimens.)

T ctZZ whom it may concern:

Be it known that I, WILLIAM CROSS, a sub-- is particularly applicable to arresting the attacks of the teredo in wharf piles and timbers and of white ants in railway-sleepers and in any other timber or material liable to attack, which I effect by impregnating the timber or other material with certain chemical solutions in the manner hereinafter explained, which consist, first, in treating the wood with a solution ofarsenious acid and an alkali, and, secondly, with a solution of sulfate of copper, which I prepare in the following manner:

A common iron boiler of the size suited to the operations to be carried on is provided. I then dissolve in every two gallons of water, by boiling, three-fourths of a pound of caustic soda or one pound of carbonate of potash (pearlash) or two and one-fourth pounds of soda-crystals. To this I add one pound of arsenic (arsenious acid) and boil the whole until thoroughly dissolved. This I will call solution No. 1. I then dissolve in every two gallons of water one pound of sulfate of copper, which solution I call No. 2. These solutions are both soluble poisons, but when combined form a nearly-insoluble poisonviz., arsenite of copper. If applied in the latter form to most materials, it would not pene trate to any extent. I therefore apply the two solutions at different times-first, solution N0. 1, which I may apply with a brush, or the timber or other material may be immersed therein or the solution forced in un-' or nearly so, I apply the No. 2 solution, which,

combining with No. 1 in the timber or other material, forms a nearlylinsoluble deadly poison, resisting for a long period the attacks of teredo, white ants, and such like insect forms and also arresting vegetable growth.

As a further protection, especially for wharf-piles and river-walls, I may employ an outer coating of tar and bitumen, which is prepared as follows: To every gallon of boiling tar I add one pound of bitumen, which I prefer to previously boil for three to four hours or until such time that by dropping a small quantity onto a sheet of metal it will leave the metal freely and without stain.

Both solutions may be applied hot or cold and the outer coating applied hot.

In treating teredo-infested timber I add to solution N0. 1 one-fourth to one-half pound yellow prussiate of potash, (ferro-cyanide of potassium.)

I do not confine myself to the exact proportions of the ingredients given. The quantities are merely approximate.

I would have it understood that I do not claim the herein-specified solutions; but

What I do claim, and desire to secure by Letters Patent, is-

The method herein described, consisting in first impregnating timber With a solution of arsenious acid and an alkali and afterward applying a solution of sulfate of copper.

In witness whereof I have hereunto set my hand in presence of two witnesses.

\VILLIAM CROSS.

Witnesses:

EDW RD HILL, JAMES HooDE. 

